Re: DHCP Migration

From: Phillip Windell (_at_.)
Date: 06/03/04 

Date: Thu, 3 Jun 2004 16:00:53 -0500

You get the one configured the way you like but leave the scopes
"deactivated". You would have a separate scope for each subnet. You
Router(s) handling the subnets would be configured to forward DHCP request
to the proper DHCP Server. When you are ready to active the scopes shut down
the old DHCP and keep it off the system, or at least disable the DHCP
Service on it, then activate the scopes on the new one.

If you are doing this with the same address set you currently use now it
will be messy and I can't see any way to avoid some downtime. We did ours
by using a whole new address block to do the splitting and left our old
address block alone and used the old one for the first subnet. This allowed
me to keep everything running as it was in the "first" subnet (old address
block) and move things a little at a time. Once the new scopes were
configured and activated on the DHCP Server and the Router was forwarding
the requests, I then took the machines in small groups and moved the patch
cable to the proper switch port and rebooted the machine or just did an
IPCONFIG "Release" and "Renew" and the machines were now in the new subnet.
Doing them in small groups reduced the effect of the "disaster" if it didn't
go well.

You have to be careful with Servers because software running on them may be
tied to their IP# and the Servers may be referenced on other machines by
thier IP#. Sometimes a software application running on a Server practically
"shoots itself in the head" if you change the Server's IP#, so there is a
lot to consider when you move a Server to another subnet. You need to
research the effects of IP# changes for every application running on the
Server, and this may even be true for some applications on the Clients. 

-- 
Phillip Windell [MCP, MVP, CCNA]
www.wandtv.com
"Joe" <joedboswell at hotmail dot com> wrote in message
news:%23Ibpk3YSEHA.3944@tk2msftngp13.phx.gbl...
> So we are installing a DHCP server on another machine in our domain with
the
> intention to have it be our primary DHCP server.
>
> At the same time we are resubnetting, going from 24 bit mask to 22 bit.
>
> I was wondering how to go about this?  Basically just setup the DHCP
server
> on the new machine and then delete all the clients on the old machine and
> use the reconcile???  I have no idea, any help in the right direction
would
> be greatly appreciated!
>
> Joe
>
>

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